Science & Technology

Why Hasn't the Mars Opportunity Rover Called Home?

Mars, we have a problem. The aging Opportunity rover stopped calling back home several weeks ago because a dust storm shut down the solar-powered machine.

What's the Problem?

Opportunity is disabled by a dust storm, but please don't imagine that fictional black blizzard portrayed in the 2015 movie "The Martian." Instead, the storm is a bunch of dust that's hovering in the planet's thin carbon dioxide atmosphere and blocking much of the sunlight. Since Opportunity needs sun to power its electronics, it's stuck right now. Too feeble even to call back home, the senior-citizen rover is probably hunkering down in a coma or safe mode, hoping for the sun to return soon.

Opportunity lifted off for Mars in 2003 and touched down on the Red Planet in 2004. It was supposed to last 90 days. Today, it's been well over 14 years! It found ample evidence for running water on the planet. It explored a couple of big craters. It even escaped a sand trap, which is really fortunate because its twin rover (Spirit) was permanently stranded in one before dying on Mars around 2010.

Human Worries for Robot Woes

We know, we know. Opportunity is just a machine. But in a sense, it's a human explorer on Mars because it's humans who plan its route and analyze its findings. It makes sense that people would be concerned about it. NASA is posting regular updates about Opportunity on its @MarsRovers Twitter account; every day, the agency listens for the plucky rover to "phone home." Also, there are people all over the Twittersphere worried about the little Martian rover and expressing their hope for its survival.

"This week, I channeled my worry into designing and stitching this @MarsRovers Opportunity, with blue for the Martian sunrise we are waiting for," wrote Alyshondra Meacham, who posted a beautiful cross-stitch rendering of the rover.

"Hang in there, Opportunity" wrote comic designer Abby Garrett, along with a cute picture of the rover setting up a makeshift communications system to stay in touch with Earth.

"Opportunity is the very essence of perseverance," wrote freelance graphics designer Beth Kerner, attaching an orange-colored decal of Opportunity.

Dust Storm Drama

NASA is carefully watching the dust storm with its fleet of spacecraft, including the nuclear-powered Curiosity rover. It's now covering almost the entire planet. The agency says it still doesn't know why some dust storms stay local, and other ones grow huge. "We don't have any good idea," stated Scott Guzewich, an atmospheric scientist at NASA Goddard Space Flight Center in Maryland who is leading Curiosity's dust storm investigation.

What NASA does know is dust storms happen more often in the southern hemisphere spring and summer, which is when Mars is closest to the sun. Carbon dioxide ice at the pole evaporates, which makes the atmosphere thicker and increases the surface pressure. At the same time, there are bigger swings in surface temperature that generate winds. Between these two phenomena, dust particles tend to stay suspended in the air, blocking Opportunity's light.

Opportunity should have enough power to stay alive, NASA said in a press conference last week, so we're certainly hoping for the best. Godspeed, little rover that could.

To learn more about the rovers exploring Mars, check out "Roving Mars: Spirit, Opportunity, and the Exploration of the Red Planet" by Steven Squyres. We handpick reading recommendations we think you may like. If you choose to make a purchase, Curiosity will get a share of the sale.

Spirit & Opportunity by the Numbers

Written by Elizabeth Howell June 25, 2018

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